On Tuesday night, LiLo, her estranged parents, her sister, and her boyfriend, Egor Tarabasov, were seen at the Duran Duran concert in Brooklyn, where the 29-year-old flashed a new sparkler on her ring finger!

Gasp!

It's pretty hard to miss the huge emerald rock sitting pretty on her left hand, accented by a slim but shiny diamond band.

And when Linds took the stage to help the duo perform Danceophobia, the whole crowd got a glimpse!! She even posted the moment to Instagram:

On Friday, a judge ruled that Lindsay and Dina Lohan's multiple lawsuits against Fox News for defamation were not admissible in court. For those who might have forgotten, Dina and Linds sued the conglomerate and a few of their anchors for alleging the two did cocaine together.

Zayn previewed the duet by posting a black and white pic of himself with Swifty on his Instagram -- but hey, she is bestiez with his girlfriend Gigi Hadid, so it wouldn't be unusual that they hang out... But collab?!